Frozen beverage product machines, such as frozen carbonated beverage (FCB) machines, traditionally utilize a time based defrost control that is periodically implemented due to build-up of ice particles in the beverage product within a freeze barrel. A defrost schedule may be manually programmed in the machine, with defrost cycles occurring either automatically according to predetermined time periods, or manually as ice particles are viewed in the dispensed beverage product and defrosting is deemed necessary. Typically, defrost cycles occur at fixed intervals, usually every 3 to 4 hours, but this approach does not take into consideration whether defrosting is actually necessary, and during defrost the machine is “down” and frozen beverage is not available for service to customers. Since “up time”, during which frozen beverage product is available for service from the machine, is very important to the user, it would be desirable to have a defrost control that puts the machine into a defrost cycle only as often as is necessary and only on an as-needed basis, thereby to increase the uptime of the machine and the amount of frozen beverage product that may be served, and also to enhance value and energy savings.